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From:   Chuanhong Guo <gch981213@gmail.com>
To:     linux-mips@vger.kernel.org
Cc:     Chuanhong Guo <gch981213@gmail.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        John Thomson <git@johnthomson.fastmail.com.au>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] MIPS: zboot: put appended dtb into a section
Date:   Mon, 26 Oct 2020 20:29:25 +0800
Message-Id: <20201026122926.1774569-1-gch981213@gmail.com>
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This will make a separated section for dtb appear in ELF, and we can
then use objcopy to patch a dtb into vmlinuz when RAW_APPENDED_DTB
is set in kernel config.

command to patch a dtb:
objcopy --set-section-flags=.appended_dtb=alloc,contents \
        --update-section=.appended_dtb=<target>.dtb vmlinuz

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
---
Note:
This should supersede this patch on linux-mips:
[2/2] mips: boot compressed: add support for vlinuz ELF DTB [0]

[0] https://patchwork.kernel.org/project/linux-mips/patch/20201015201100.4130-2-git@johnthomson.fastmail.com.au/
 
 arch/mips/boot/compressed/ld.script | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/mips/boot/compressed/ld.script b/arch/mips/boot/compressed/ld.script
index 2ed08fbef8e7..0ebb667274d6 100644
--- a/arch/mips/boot/compressed/ld.script
+++ b/arch/mips/boot/compressed/ld.script
@@ -31,9 +31,12 @@ SECTIONS
 		CONSTRUCTORS
 		. = ALIGN(16);
 	}
-	__appended_dtb = .;
-	/* leave space for appended DTB */
-	. += 0x100000;
+
+	.appended_dtb : {
+		__appended_dtb = .;
+		/* leave space for appended DTB */
+		. += 0x100000;
+	}
 
 	_edata = .;
 	/* End of data section */
-- 
2.26.2